Lifting-jack.



G. H. OBERBECK, DECD.

G- OBERBECK. ADMINISTRATRIX.

LIFTING JACK.

APPLICATION FILED OC 9, I915.

Patented Aug. 29, 1918.

3 SHEETS-SHEET I.

Z52 GUfiTAV H. DBERBEQK, DECEASED, W TRUDE DBERBELK. ADMmlsrRArRm,

G. H. OBERBECK, DECD.

G OBERBECK. ADMINSSTRATRIX LIFTING JACKx m APPLICATION FILED OCT. 9, I9l5. mi h aa,

Patented Aug. 29, 1916.

3 SHEETS-SHEET 2- G. H. OBERBECK, DEC'D. e. OBERBEUK, ADMINISTRATRIX.

LIFTING JACK.

APPLICATION FILED OCT. 9, 1915.

Patented Aug. 29, 1916.

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GUSTAV I-I. OBEBBECK, DECEASED, LATE OF ST. LOUIS. MISSOURI, BY GERTRUDE OBER- BECK, ADMINISTRATRIX, OF ST. LOUIS, MISSOURI, ASSIGNOR 01E ONE-HALF TO NEALY J. TOWNSEND, OF ST. LOUIS, MISSOURI.

LIFTING-JACK.

Specification of Letters Patent.

Iatented Au". 29, 19165.

Application filed October 9, 1915. Serial No. 55,096.

b all whom it may concern:

Be it known that Gus'rav II. OBERBECK, deceased, late a citizen of the United States, and a resident of the city of St. Louis, State of lt iissouri, did invent certain new and useful Improvements in Lifting-Jacks, of which the following is a specification.

This invention relates to improvements in lifting jacks, one of the objects being to produce a strong and simple lifting jack having an extensible carrier or lifting bar, composed of sections which primarily lie in approximately the same horizontal plane and which are adapted to be shifted upwardly into different horizontal planes, thereby producing a comparatively low or short jack capable of being placed in a comparatively small space, under the object to be lifted; and then extended to lift the object a greater distance than the height of any single section of the carrier or lifting bar.

The preferred form of the invention comprises an extensible carrier, or lifting bar, consisting of a primary section and a secondary section, each of said sections having a row of teeth, operating means adapted to cooperate with the teeth of the primary sectionto lift it independently of said second ary section, and means for uniting said sections to permit them to be lifted simultaneously, the operating means being adapted to cooperate with the teeth of the secondary section after the two sections have been united.

Another object of the invention is to produce a simple double acting lifting jack.

lVith the foregoing and other objects in view the invention comprises the novel. construction, combination and arrangement of parts hereinafter more specifically described and illustrated in the accompanying drawings wherein is shown the preferred embodiment of the invention; however, it is to be understood that the invention comprehends changes, variations and modifications which come within the scope of the claims hereunto appended.

Figure I is a side elevation of a lifting jack constructed in accordance with the invention, the upper portion of .the support, or pedestal, being broken away. Fig. II is a vertical section taken approximately on the line X-X, Fig. I, looking in the direc tion indicated by the arrows II. Fig. III

is a horizontal section taken approximately on the line III-III, Fig. IV. Fig. IV is a vertical section taken approximately through the center of the jack. Fig. V is a vertical section taken approximately on the line X X, Fig. I, looking in the direction indicated by the arrows V. Fig. VI is a side elevation of the upper portion of the jack, showing the sections of the carrier in their extended positions, the feeding pawl and retaining pawl being omitted. Fig. VII is a front elevation of the parts shown in Fig. VI. Fig. VIII is an enlarged section on line VIIIVIII, Fig. VI, showing the latch dogs for uniting the elements of the sectional carrier. Fig. IX is an en larged section on line IX-IX, Fig. VI. Fig. X is an enlarged section on line X-X, Fig. VI, showing the means for unlocking the latch dogs to permit one of the carrier sections to move independently of the other. Fig. XI is a side elevation, partly in section, showing the double acting pawls as they appear during the downward movement of the carrier.

A designates a supporting frame, or pedestal, having a pair of vertical guide ribs 1, see Figs. III, VI and VII. The lifting bar, or carrier, is an extensible structure comprising a secondary section S, and a primary section P arranged within and slidably fitted to said secondary section. The secondary section is preferably channel shaped in cross section and it has a pair of grooves 2 for the reception of the vertical ribs 1 on the pedestal. The secondary section is thus slidably fitted to the pedestal and guided in its movements by the ribs 1 which lie in the grooves 2. Vertical grooves 3 are formed in the primary section F to receive vertical guide ribs 4 which extend inwardly from the secondary section S, as shown most clearly in Figs. VI and X. A head 5, formed on the upper end of the primary section, is adapted to form a seat for the object to be lifted.

The secondary section S has two rows of rack teeth 6, the primary section P is provided with a single row of rack teeth 7 which lie between the rows 6, see Fig. II. The row of rack teeth 7, on the primary section, extend upwardly to a plane beyond the teeth 6, where they will be engaged by a feed pawl 8 during the initial upward forcing the y 10 in a corresponding direction to force thelr feed pawl 8.

- teeth of the movement of the jack. It is to be noted that the secondary section has toothless faces 9 which lie opposite the operating edge of the feed pawl 8 when the parts occupy the positions shown in Figs. I and II. 10 designates a retaining pawl, pivoted to the pedestal 12, and adapted to engage the teeth6 and 7. The feed pawl 8 is pivoted at 13 to an operating lever 14, the latter being pivotally supported at 15 by the pedestal A. A member 16, preferably a wire or small rod, is loosely secured at its upper end to a finger 8' extending downwardly from the This member 16 passes through an opening 17 in a spring 18 and its lower end is slidably fitted to the lower end of the retaining pawl 10.

When the parts occupy the positions shown in Figs. I and IV, the spring 18 tends topull the member 16 to the right, thereby lower ends of the pawls 8 and operating edges into engagement with the primary and secondary sections. To understand: the action of the pawls during thelifting operations, it will only be necessary to bear in mind that the spring 18 forces both pawls into engagement with the rack teeth, and that the feed pawl 8 moves upwardly and downwardly in response to movements of the operating lever 14.

The sections]? and S which constitute the extensible carrier, orlifting bar, have been termed a primary section and a secondary section on account of the peculiar manner in 7 gagement with the feed which they are operated by the feeding device. At the beginning of the lifting-operation the primary section P is-engaged by thefeedpawl 8 having the toothless faces 9 which then lie opposite the feed pawl as seen in Fig. I. After the primary section has been lifted a predetermined distance it is automatically united, withthesecondary, section S, and both sections then move simultaneously in response to the operation of the feed pawl Asthe secondary section S moves upwardly its rack teeth 6 are brought into enpawl 8 during the secondary, or final lifting movement.

The'means for uniting the primary and secondary sections to'permit them to move simultaneously, comprises a pair of latch dogs 20 carried by the primary section P and adapted to enter openings 21 in the secondary'sectiomto unitesaid sections after the primary section has been lifted a predetermined distance. The latch dogs 20 are arranged within the lower portion of the primary section P and pivotally secured thereto by means of screws 22. Springs 23 (Figs. IV'and VIII) tend to force the latch dogs away from each other and it moves upwardly independently ofthe secondary section, the latter the secondary section S and when the latch dogs reach the openings 20, near the upper end of section S, they are forced into said openings to connect the primary section to the secondary section. At this time the feed pawl 8 engages a tooth on the lower portion of the primary section P, and as said primary section continues its upward movement in response to the operation of feed pawl 8 both sections move simultaneously for the reason that they are united by the latch dogs 21. As both sections continue such upward movement, the feed pawl 8 engages the rows of rack teeth 6 on secondary section. 2-1 designates a stop lug formed on the lower portion of the secondary section S and adapted to engage a bolt 25 on the pedestal A to limit the upward movement of the sectional carrier.

The means for reversing the action of the pawls 8 and 10 to permit the sectional carrier to move downwardly in response to movements of the operating lever 14, comprises a rock shaft 26, journaled in the pedestal A, and provided with a flat face 26 which engages the spring 18 (Figs. I and IV) during the upward movement of the carrier. An operating handle 27, fixed to the rock shaft 26, may be shifted from the position shown in Fig. I to the position shown in Fig. XI so as to force the spring 18 away from the axis of the rock shaft 26. It has been explained that the spring 18 tends to force both pawls into engagement with the rack teeth when the parts occupy the position seen in Figs. I and IV; however, after the rock shaft has been turned to the position shown in Fig. XI, said spring 18 tends to force bothpawls away from the rack teeth. When the parts occupy the last mentioned position (Fig. XI) the spring 18 forces the rod 16 to the left, thereby forcing the lower portions of the pawls 8 and 10 in a corresponding direction so as to force their upper ends away from the rack teeth. The upper portion of the feed pawl 8 is forced into engagement with a cam face 28 (Fig. XI) on the upper portion of the pedestal A. When the operating lever 14 is shifted from the position shown by full lines in Fig. XI to the position shown by dotted lines, the feed pawl 8 moves downwardly, thus permitting the sectional carrier to drop by gravity, and after the carrier has moved downwardly a slight distance, the inner end of the operating lever 14: engages a cam face 29 on the retaining pawl 10 so as to shift said retaining pawl into engagement with one of the teeth. The feed pawl finally passes from the tooth and the retaining pawl 10 then serves as a stop for limiting the downward movement of the carrier. For example the feed pawl may primarily engage the shoulder designated 6 in Fig. XI, while the retaining pawl 10 occupies the position shown in full lines. After the feed pawl has moved downwardly a distance equal to about one-half of the len th of a tooth, the retaining pawl 10 is shifted to a position immediately below the shoulder 6". Thereafter the feed pawl 8 moves to the position indicated by dotted lines and the carrier drops by gravity until the shoulder 6 strikes the retaining pawl 10.

Then the parts are moving from the position shown by dotted lines (Fig. XI) to the positions shown by full lines, the feed pawl moves upwardly and inwardly where it will cooperate with a tooth to prevent or limit the downward movement of the carrier, and the retaining pawl then moves away from the toothed carrier. During such movements, the feed pawl 8 is guided by the cam face 28 on the pedestal, and the retaining pawl 10 is positively released from the teeth by the action of the rod 16 which passes through the upper end of spring 18. This rod 16 acts as a lever. It is fulcrumed at the opening 17 in the spring 18 and when the parts move from the positions shown by dotted lines to the positions shown by full lines, the lower end of the rod 16 moves to the left, and the lower portion of the retaining pawl 10 moves in the same direction, thereby positively moving the upper end of the retaining pawl away from the teeth. The sectional carrier moves downwardly, step by step, in response to the movements of the operating lever 14, and immediately before the primary section P reaches its lowermost position the feed pawl 8 is forced into engagement with an unlocking device F to release the primary section from the secondary section.

The unlocking device F is a Y shaped member (Fig. X) having a head 30 which projects from the toothed face of the primary section P as shown in Figs. VI and VII. It is also provided with a pair of inclined faces 31 (Fig. X) which lie on opposite sides of the latch dogs 20, and it is slidably fitted to the primary section P. When the unlocking device F is forced inwardly by the feed pawl 8, the latch dogs 20 engaging the inclined faces 31 (Fig. X) are forced toward each other and withdrawn from the openings 21, in the secondary section S. This releases the sections from each other, and the primary section P, tending to drop by gravity, is permitted to fall step by step in response to the action of the pawls 8 and 10. During the downward movement of the primary section P, and immediately after the unlocking device F neously in response has been forced inwardly, the Vshaped inner edges 40 of said unlocking device engage a cam 33, formed on the secondary section as shown in Figs. III and IV.

When these V-shaped inner edges of the unlocking device F travel along the cam 33, the unlocking device is positively forced outwardly to its normal position. The cam 33, cooperating with the V-shaped edges 40,

therefore serves as means for restoring the unlocking device F after the latter has been pushed inwardly by the feed pawl. However, this cam 33 is only an auxiliary re storing device, intended to insure a positive action. The spring-pressed dogs 20, engaging the inclined faces 31 on the unlocking device F (Fig. X) serve as means for restoring the unlocking device to its normal position. When the spring-pressed dogs 20 are forced into the openings 21, at the up per end of section S, said dogs bear against the inclined faces 31 with the result of forcing the unlocking device outwardly to the position shown in Fig. X.

What is claimed as new and desired to be secured by Letters Patent is 1. In a lifting jack, an extensible carrier comprising vertically movable sections, operating means adapted to lift one of said sections independently of the other, a dog carried by one of said sections and adapted to cooperate with the other section to permit both sections to rise in response to movements of said operating means after one of the sections has been lifted a predetermined distance, and means, operable by said operating means, for releasing said dog to permit one of said sections to move downwardly independently of the other.

2. In a lifting jack, an extensible carrier comprising sections, one of which is movable independently of the other, a latch device carried by one of said sections, said latch device including a latch dog for uniting said sections, and a releasing device adapted to cooperate with said latch dog to disconnect the sections, and operating means adapted to lift one of said sections independently of the other when the latch dog occupies its inoperative position, said latch dog being movable automatically to connect the sections, and said operating means being adapted to actuate said releasingdevice to disconnect the sections.

3. In a lifting jack, an extensible carrier comprising vertically movable sections, operating means adapted to lift one of said sections independently of the other, a pair of spring pressed latch dogs for uniting said sections to permit them to move simultato movements of said operating means, and a cam for releasing said latch dogs, said cam being operable by said operating means.

4.. In a lifting ack, an extensible carrier the primary section has been lifted a predetermined distance, and an uncoupling device for releasing said automatic coupling device to permit said secondary section to move downwardly independently of said primary section,- said uncoupling device including a releasing member operable by said 7 operating means.

5. In alifting jack, an extensible carrier comprising a toothed primary section and a toothed secondary section, operating means for lifting said primary section independently of said secondary section, said operating means including a feed pawl adapted to engage the teeth of both of said sections, an automatic coupling device for uniting said sections to permit both of them to move upwardly in response to movements of said feed pawl after the primary section has been lifted a predetermined distance, and an uncoupling device for releasing said automatic-coupling device to permit said secondary section to move downwardly independently of said primary section, said uncoupling device including a releasing member operable by said feed pawl.

GERTRUDE OBERBECK, Administmatm'm of the estate of Gustav H.

Obe'rbeck, deceased.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

, a 7 Washington, D. G. 

